The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

There’s a hidden military meme engraved on the World War II Memorial.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

A Civil War fort in the middle of Washington, D.C. has been swallowed by a forest.

The walls of the iconic dome are hollow and have a secret stairway.

A nostalgic bibliographic gem.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

Home to items never before seen by the public.

The site of the climactic scene from the classic horror film is now a historic landmark.

Latvia's symbolic mountain-shaped national library is home to millions of cultural tomes.

The Guardian of Tallinn.

This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

Sitting beneath an unremarkable residential building is a museum devoted to classic Pinball.

Uh, pardon me, ma'am, but I couldn't help noticing that there's a Columbo statue in the middle of Budapest.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A statue in Budapest's Liberty Square honors the former U.S. president's efforts to end the Cold War.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

This floating sculpture of ice is a poignant reminder of nature's power.

Home to three historic ships from the age of Vikings.

The oldest Jewish cemetery in Europe survived Hitler's Germany.

This tremendous timepiece was once the largest cuckoo clock in the world.